With conventional basement construction, basement walls are typically built from concrete. However the number of concrete block basements being built has steadily declined over the past three decades. The reason for the decline in the use of a traditional 20 cm (8 in.) hollow concrete block basement is that they are no longer technically viable. Specifically the desire for greater wall heights in basements so as to allow for increased head room, and the trend of having backfill near to the top of the basement wall have raised a number of technical difficulties. Basically both factors significantly increase the bending moments which current basement walls are not designed to resist. While thicker walls using larger hollow concrete blocks or reinforced 20 cm (8 in.) blocks are satisfactory technical solutions, these solutions result in significantly increased costs and thus negatively affect the competitive position of a concrete block basement.
Other basement systems such as wood and precast concrete have not succeeded due to high costs, construction difficulties, and durability concerns. Furthermore a non-reinforced poured-in-place concrete system typically experiences cracking and water penetration problems. There are also significant cost increases due to attempting to form non-standard heights and configurations as well as providing additional reinforcing to overcome the cracking problem. One solution to some of these problems is the use of insulated concrete form (ICF) systems but the costing is generally unacceptable for most housing projects. Another solution for reinforcing concrete block basements is to use relatively small amounts of vertical and horizontal reinforcing bars. However the increased cost of reinforcing and grouting the basement walls, as well as the added construction experience and expertise required of house builders have resulted in resistance to adopting this system.
Other potential solutions include the use of fibre reinforcement either in vertical and horizontal strips or with full wall coverage by epoxy attachment of fibre cloth. However, the structural fibre materials, the epoxy, the application, and the anchorage of the edges (ends) to prevent delamination all result in increased costs. Furthermore this application is also sensitive to weather and wall surface conditions including flatness.
Prior art reinforcement mechanisms and constructions systems have been devised to address some of the noted problems. For example, U.S. Pat. No. 5,535,556 issued on Jul. 16, 1996 to Hughes, Jr. relates to a basement wall is formed by a series of vertical metal studs supported at their lower ends on a metal sill extending along the upper face of a concrete footing. An insulating sheathing is mounted on the metal studs to form the wall outer surface. The sheathing is formed by two panel layers of rigid foam core insulator material. Edges of the inner panels are offset from the edges of the outer panels to form labyrinth seals preventing migration of ground water through the sheathing.
Norton et al. is the owner of U.S. Pat. No. 4,452,028 which issued on Jun. 5, 1984 and relates to a structure and method for reinforcing a wall including a plurality of blocks having vertically aligned passages and a sill plate positioned on top of the blocks. An opening is formed into one of the passages and lower and intermediate reinforcing bars are inserted through the opening and into the vertically aligned passages. An aperture is formed in the sill plate above the vertically aligned passages and an upper reinforcing bar is extended through the aperture and positioned partly within the vertically aligned passages, wherein it is connected to the lower and intermediate reinforcing bars, thereby forming an elongate reinforcing member. A cementous material which cures to a hardened state is placed in the vertically aligned passages whereby the elongate reinforcing member is fixedly attached to the wall therein. An upper portion of the upper reinforcing bar is threaded and adapted to threadably receive a nut which engages the sill plate.
U.S. Pat. No. 4,024,688 which issued on May 24, 1977 to Calini relates to a method and construction for joining the ends of concrete reinforcing bars which permits the development of both tension and compression in the bars. A joining member compressively engages adaptor members integrally joined to the ends of the bars and reacts any forces tending to separate the bars, and further permits transmittal of compressive forces there between.
Finally U.S. Pat. No. 4,563,852 which issued on Jan. 14, 1986 to Achtenberg et al. and relates to a method by which a concrete block foundation wall is strengthened and reinforced. Upper and lower access openings are chiseled in the wall to provide access to a vertical passage formed by aligned cavities in the blocks. A lower anchor bolt is inserted through the lower opening and anchored to the foundation wall footing at the bottom of the passage. An upper bolt is inserted through the upper opening and extended through the wood plate which rests on top of the wall. A nut is threaded onto the upper bolt. A flexible steel cable is inserted into the passage through the upper opening and fastened to the upper bolt at one end and to the lower bolt at the other end. The nut is then tightened on the upper bolt to place the cable in a taut condition. A spacer is inserted through an intermediate opening in the wall and used to deflect the cable to a bowed shape. The passage is then filled with cement to form a vertical column of cement reinforced by the steel cable.
Prior art patents however do not address the following needs. Specifically, as modern house construction has increasingly relied on making basement space a habitable area, there is a need to provide sufficient resistance to soil pressure against concrete block basement walls that have increased height for added head room. Furthermore as the use of basements as desirable living space and implementation of energy saving regulations require providing insulation, air/vapour barriers, and an interior finish, the ability to have some form of strapping attached to the basement wall to serve as the platform for holding insulation in place as well as providing support for dry wall or other paneling is also desired. Overall, the finishing of the basement is an added cost but one that is very cost-effective in terms of creating useable space. A heavily insulated basement also allows the builder to use energy trade-offs to justify large above grade window areas.
Thus an improved reinforcing shaped member and a system for construction using the same for application in a concrete block basement wall which addresses the above noted needs is desirable.